Convert an iterator to set in Java

Write a function toSet, that takes an iterator as an argument and return the set as output.

 

Signature

public static <T> Set<T> toSet(Iterator<T> iterator)

 

Find the below working application.

 

IteratorToSet.java

package com.sample.app.collections;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class IteratorToSet {

	/**
	 * Convert an {@link Iterator} to the {@link Set}
	 * 
	 * @param <T>
	 * @param iterator
	 * 
	 * @return empty set, if the iterator is null, else return a set that contain
	 *         the elements from iterator
	 */
	public static <T> Set<T> toSet(Iterator<T> iterator) {

		if (iterator == null) {
			return Collections.emptySet();
		}

		final Set<T> set = new HashSet<>();

		while (iterator.hasNext()) {
			set.add(iterator.next());
		}

		return set;
	}

	public static void main(String[] args) {
		Iterator<Integer> primesIter = Arrays.asList(2, 3, 5, 7, 11).iterator();

		Set<Integer> primesSet = toSet(primesIter);
		System.out.println(primesSet);
	}

}

 

Output

[2, 3, 5, 7, 11]

 

 

  

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